The UNIQUE constraint in PostgreSQL violated when more than one row for a column or combination of columns which have been used as a unique constraint in a table. Two NULL values for a column in different rows i
create unique index idx_uniq_id_info_indext on index_t(id,info) ; maleah_db=# insert into index_t values (1,2,3,'test') ; INSERT 0 1 maleah_db=# select count(*) from index_t where id = 1 ; count --- 2 (1 row) 可以看到,可以插入id字段的重复值,在这种情况下,只能使用INCL...
then the UNIQUE constraint generates an error stating that the specified value already exists in the table. In PostgreSQL, a unique index is automatically created when we insert a UNIQUE constraint
constraint_type有四种:UNIQUE、PRIMARY KEY、CHECK、FOREIGN KEY 通过修改上边sql语句的table_name和constraint_type来进行相应的查询 警告
util.PSQLException: ERROR: duplicate key value violates unique constraint "xxl_job_info_pkey" 是主键冲突异常,每次插入数据时重新确认自增主键的取值,而是会使用缓存提高效率。 这就导致某些情况下插入数据(例如SQL语句中指定了ID)不会更新这个自增主键下一个取值的缓存,进而在下次插入时触发错误。 2 解决 代码...
UNIQUE constraint –ensure that values in a column or a group of columns are unique across the table. NOT NULL constraint –ensure values in a column are not NULL. DEFAULT constraint –specify a default value for a column using the DEFAULT constraint. Section 14. PostgreSQL Data Types in Dep...
Fixed issue of blocking of UNIQUE constraint/index on nullable column not implemented consistently. Fix a crash with T-SQL OPENQUERY() and four-part object name when T-SQL keywords are used as server name. Fixed the issue of update with TOP, OUTPUT and join failing with error ‘unrecognized...
For example, if there's a unique constraint on a field such as a social security number, a user may not insert a duplicate row, meaning they can't access it, but they can deduce that a record with that social security number exists. By default, RLS is disabled on tables in ...
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CREATE TABLE devices ( device_id bigint primary key, device_name text, device_type_id int ); CREATE INDEX ON devices (device_type_id); -- co-locate the devices table with the events table SELECT create_distributed_table('devices', 'device_id', colocate_with := 'events'); -- insert...